A Programmable Logic Controller (PLC) is a digital computer used for automation of processes such as assembly lines. A single installation may have hundreds or even thousands of PLC devices interconnected to one another, and these devices are commonly under control of a single PLC program, written in ladder logic or other languages, with each device having a dedicated set of PLC code. This can result in a PLC program having tens of thousands of lines of code, which necessarily creates management and quality control issues.
To minimize these issues, it is conventional for institutional users to adopt a tag naming convention as well as a standard PLC tag and logic file. The tag naming convention consists of a plurality of fragment values which are adopted consistently as needed. The standard PLC tag and logic file includes a plurality of generic code sets applicable to different broad types of equipment. This consistency renders it easier to introduce programmers to a project team, as the new programmers can more readily follow the logic and flow.
However, even with conventions and standard logic, project coding can be labor intensive; in the creation of a PLC program for a project, it is conventional for coders to manually replicate a portion of the standard logic for each piece of equipment and to manually customize the code thereafter. Projects can entail hundreds or thousands of hours of effort and even if skilled programmers are used, it is not uncommon for errors to occur, which can result in significant efforts spent debugging.